abHiooooo7

Hi there.. I'm running the following system currently: >Intel® Core™ i7-4790K Processor 4.0 GHz (8M Cache, up to 4.40 GHz) (88W) >Gigabyte GA-Z97X Gaming 3 Motherboard >Team 8GB (2x4) Heat-Sync Dual Kit RAM 2133 BUS >Samsung BX2450 24" LED Display (1920x1080) >Thermaltake Chaser A41 Gaming Chasis >Thermaltake Water 3.0 Performer Water Cooler >Samsung 2TB HDD >Transcend 128GB SSD >Cable TV Tuner >Webcam, 1 external HDD >CPU has two 140mm LED fans and a 200mm LED fan I'm currently using this PSU >Thermaltake 550W PSU Black Edition I currently have no GPU's.. bt I'm planng to buy a >Asus GeForce GTX 770 DirectCU II OC OR >Asus R9 280X DirectCU II my question is: **Which GPU should be better for playing on ultra settings on a 1080p display? **Will my PSU be enough.. or do I need to upgrade it?